1. Field of the Invention
The invention relates to paper machine press sections and somewhat more particularly to an arrangement which conveys a new web from a forming surface to dewatering presses without any open draws and conveys the web through at least a reverse press in a completely supported manner and permits easy removal of broke.
2. Prior Art
Many paper machine felt transfer and press arrangements are known. However, with increased modern-day high capacity paper machines capable of running at speeds in excess of 3000 to 7000 feet per minute, these known arrangements exhibit various drawbacks, such as insufficient web support, excessive wrap about one or more guide or press rolls, improper press roll alignment for proper web travel, insufficient dewatering capacity, excessive machine space requirements, excessive felt length requirements, etc.
For example, U.S. Pat. No. 2,204,446 illustrates forms of prior art felt transfer and press arrangements wherein the felt and press rolls are so arranged to cause the wire-side of the web to contact a plain press roll and thereby eliminate wire markings on the web. However, the travel path of the felt-supported web through the press nips involves a number of sharp turns which are detrimental at high speeds and improper felt and press roll arrangement in this system limits the dewatering capacity of the arrangement.
U.S. Pat. No. 2,764,068 illustrates another form of prior art felt transfer and press arrangement wherein the felts and press rolls are arranged, along with a movable doctor, to dump a portion of the broke from the arrangement during start-up procedures. However, improper roll sequence at the first press nip prevents the web from reliably following its intended path of travel and improper felt guidance over certain of the press rolls causes excessive re-wetting thereof which leads to operational difficulties. Further, the doctor arrangement makes it extremely difficult to re-thread the arrangement with a full width sheet (web) and this arrangement is not suitable for modern-day high speed paper machines.
Other prior art felt transfer and press arrangements are also known, for example, typical prior art arrangements are shown in U.S. Pat. Nos. 1,930,104; 2,386,584; 3,198,696; 3,268,390; 3,515,637; 3,355,350; 3,595,745; etc. These arrangements have one or more of the drawbacks set forth above, especially when combined with high speed paper machines.